This invention relates to an improved dental matrix retainer and, particularly, a novel retainer for use in filling a cavity whereby the filling material protrudes beyond the cavity into contact with an adjacent tooth.
Dental matrix bands or retainers have been known and utilized for a considerable period of time for looping around an axial contour of a tooth which is to be restored. The band is fashioned with an aperture through which filling material may be inserted into a cavity on the side of the banded tooth. The band is maintained in snug embracing relation with the axial contour of the tooth during the restoration in order to shape the filling by forming a temporary wall for the filling material.
However, it has been found in many circumstances that it is desirable for the filling material to protrude beyond the cavity into contact with an adjacent tooth to prevent further diseases and discomfort caused by many restorations. With the prior known dental matrix retainers, with the central apertures, it is impossible to remove the matrix band without disturbing the contact point between the teeth or the restoraton. This invention is directed to solving this problem by providing a new and improved dental matrix retainer.
Accordingly, an object of the present invention is to provide a dental matrix retainer of the character described which is in the form of a split band having a pair of elongated adjacent band portions which are wrapped about a tooth adjacent parallel relationship. The band portions have a pair of opposed notches, one formed in the adjacent edge of each band portion for cooperating with the notch of the other band portion to define a singular aperture through which filling material may protrude into contact with an adjacent tooth. In this manner, after the cavity has been filled and the tooth restored the two band portions can be transversely separated and removed longitudinally from between the teeth without disturbing the contact point or the restoration.
In one form of the invention, the split band portions are separate individual bands having the notches cut out of the edges thereof whereby the bands may be looped about the axially inner or gingival contour of a tooth and the axially outer or cusp contour of the tooth with the notches in opposed alignment to form the aperture.
In another form of the invention, the matrix retainer is unitary with the two elongated adjacent band portions formed from a single sheet of thin material for looping about a tooth. The band portions are integral at adjacent ends and separated at opposite ends, with the opposed notches aligned in adjacent inner edges of the band portions to define the singular aperture.
In either form of the invention, means is provided to removably maintain the bands or band portions snugly about the contours of the respective portions of the tooth to be restored. The maintaining means comprises longitudinal series of transverse slots at one end of the bands are in the interconnected portions of the unitary band. The opposite ends of the bands or band portions are sufficiently narrow for positioning in a selected one of the slots and a raised detent is engageable within the slot to maintain the bands or band portions snugly about a tooth. Of course, the slots and detents can be eliminated and a standard clamping block used to maintain the bands about a tooth.
Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings.